Food poisoning is one of the most serious public health problems in cities around the world. Various toxins in food may affect the health of the consumers. Therefore, the quality of food must be examined to ensure that some poisonous or hazardous toxins do not exist in food.
The concentration of toxins may be determined by using testing agents. The traditional chemical testing approaches are time consuming and may not response promptly. Alternatively, material characterization techniques in laboratories may be used to analyse the concentration of a target substance and even the composition of a testing sample. Although the results may be very accurate and sensitive, these techniques used in laboratories may not be suitable for daily applications which may require prompt and low-cost testing results.